High Voltage Overhead Power Lines - Protaras plot
The measurements were performed on the 16th of December 2009 at 10:45 am during cloudy weather conditions. The EMF measurements were performed at the point of interconnection of plot area and the Protara Transmission Substation and in direct proximity to the 132 kV and 11kV overhead power line.
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Figure 1: Plot area |
Figure 2: Area of maximum magetic field |
The overhead power line is rated at a nominal power of 290 MVA. At the time when the measurements were performed, the load of the overhead power line was 17.1 MVA. The Resultant Load of all three phases was 5.9% utilisation of the nominal load power:
Limiting exposure values have been provided by the ICNIRP recommendations and are guidelines to many countries and organizations. The exposure limits at 50 Hz are tabulated in the following table according to the limits given by ICNIRP.
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Reference levels for Occupational exposure ICNIRP |
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Frequency |
Electric Field Strength, E (V/m) |
Magnetic Field Strength, H (A/m) |
Magnetic Flux Density, B (µT) |
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50 Hz |
10000 |
400 |
500 |
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Reference levels for General Public exposure ICNIRP |
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Frequency |
Electric Field Strength, E (V/m) |
Magnetic Field Strength, H (A/m) |
Magnetic Flux Density, B (µT) |
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50 Hz |
5000 |
80 |
100 |
Table 1: ICNIRP Exposure limits for Occupational and General Public exposure
The maximum obtained values are represented below and compared to the ICNIRP specified limits of General Public standards. The highest magnetic field was observed on the left of Protaras Transmission Substation, with a value 0.56 μT (6m away from the starting point) and a percentage of 0.56 % as compared to the ICNIRP General Public standard. The following table summarizes the highest recorded measured values for magnetic field.
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Magnetic Field Measurements |
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Distance from Side /m |
Maximum Magnetic Field [μT] at Z Height /m - Percentage of ICNIRP General Public Standard /% |
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0.3m |
ICNIRP % |
1m |
ICNIRP % |
1.75m |
ICNIRP % |
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Measurements along the 132kV Overhead Power Line |
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26m |
0.18 |
0.18% |
0.21 |
0.21% |
0.20 |
0.20% |
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Measurements across the 132kV Overhead Power Line |
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26m |
0.14 |
0.14% |
0.14 |
0.14% |
0.15 |
0.15% |
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Measurements inside the plot area behind the Transmission Substation |
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30m |
0.22 |
0.22% |
0.22 |
0.22% |
0.24 |
0.24% |
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Measurements inside the plot area |
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50m |
0.43 |
0.43% |
0.49 |
0.49% |
0.56 |
0.56% |
Table 2: Magnetic Field Measurements
The highest electric field was observed below the 132 kV overhead power lines, with a value 0.025 kV/m and a percentage of 0.5 % as compared to the ICNIRP General Public standard. The following table summarizes the highest recorded measured values for electric field.
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Electric Field Measurements |
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Distance from Side /m |
Maximum Electric Field [kV/m] at Z Height /m - Percentage of ICNIRP General Public Standard /% |
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0.3m |
ICNIRP % |
1m |
ICNIRP % |
1.75m |
ICNIRP % |
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Measurements inside the residence-Left side of the substation |
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Point A |
-- |
-- |
-- |
-- |
0.018 |
0.36% |
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Point B |
-- |
-- |
-- |
-- |
0.012 |
0.24% |
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Point C |
-- |
-- |
-- |
-- |
0.025 |
0.50% |
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Point D |
-- |
-- |
-- |
-- |
0.006 |
0.12% |
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Point E |
-- |
-- |
-- |
-- |
0.006 |
0.12% |
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Point F |
-- |
-- |
-- |
-- |
0.006 |
0.12% |
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Point G |
-- |
-- |
-- |
-- |
0.012 |
0.24% |
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Point H |
-- |
-- |
-- |
-- |
0.006 |
0.12% |
Table 3: Electric Field Measurements